Refrigerating apparatus



Patented July 1, 1930 UNITED STATES FRANK W. ANDREWS, OF DAYTON, OHIO,

ASSIGNOR, BY MES NE ASSIGNMENTS, TO

FRIGIDAIRE CORPORATION, A CORPORATION OF DELAWARE REFRIGERATING APPARATUS Application filed April 28,

The present invention relates to refrigerating systems and particularly that type of refrigerating system in which the flow of refrigerant to the evaporator of the system is controlled automatically.

= One of the objects of the present invention is to increase the efliciency of refrigerating systems and this object is carried out by providing an automatic pressure reducing valve which will maintain automatically various pressures in the evaporator most suitable for various conditions of the refrigerant in the evaporator.

Another object of the present invention is to simplify the construction of the automatic pressure reducing valve by eliminating movable parts.

In the present invention the valve which regulates the flow of refrigerant medium to the evaporator is provided with a restrictive passage permanently open, and the system is constructed and arranged whereby the refrigerant medium is cyclicall withdrawn from the evaporator. Anot er object of the present invention is to'provide means for preventing the flow of refrigerant through the evaporator when refrigerant medium is not bein withdrawn therefrom by the compressor 0 the system.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawings Fig. 1 is a diagrammatic view of a refrigerating system showing one form of my improvement and,

Fig. 2 is a longitudinal sectional view of a pressure reducing valve utilized in this system.

Referring to the drawings, there is shown a compressor 20 which is driven by a motor 4 21. Refrigerant medium is conducted to the 1927. Serial No. 187,350.

'the compressor by a pipe 23 to a condenser 24 in which it is liquefied and collected wlthin a receiver 25. Liquefied refrigerant is delivered from the receiver 25 to an evaporator 27 through a pipe 28. The fiow of refrigerant from the pipe 28 to the evaporator 27 is controlled by a pressure reducing valve 30. 5

Valve 30 includes a main body portion 5 31 provided with a chamber 32. The body 31 includes an outwardly extending hollow boss 33 which is internally threaded for connection with the pipe 28. One wall of the chamber 32 comprises a disc 35 which rests against a shoulder 36 which disc is clamped against the shoulder by a nut 37 screwthreaded through one end of the body 31. A coupling 38 is also threaded into this end of the body 31, which coupling is also connected with the evaporator 27 The disc 35 is provided with a centrally disposed orifice- 40, which orifice provides permanent intercommunication between the pipe 28 and the evaporator 27 The disc 35 is formed from material havin a high coefiicient of expansion whereby t e diameter of the orifice is increased and decreased in response to the increase and decrease of temperature.

The orific is relatively small and is apt .to become clogged after an extended period of operation. A device, which forms a part of the valve 30, is provided for cleaning out the orifice. This device comprises a pin 41. disposed concentrically with respect to the orifice 40 and is carried by a stem 42 which is screw-threaded into the body 31 as at 43. Stem 42 extends through the body 31 and is provided with a keyhold 44 by which the stem may be rotated and which rotation will force the pin 41 through the orifice 40. The stem 42 is provided with a valve 46 which cooperates with a seat 47 formed by the body 31. Valve 46 normally rests on the seat 47 0 to prevent the escape of refrigerant about the stem 42. A packing 48 is provided around the outer edge of the stem 42 to pre vent the escape of refrigerant about said.

stem. while the stem 42 is being manipulated.

The circuit to the motor 21 is controlled preferably by a temperature responsive snap switch 50. This switch is actuated by a pressure responsive bellows 51 which is connected by a pipe 52'to a thermostatic tube 53. The switch is so computed that when the temperature, of the evaporator or the compartment cooled by the evaporator, attains a predetermined low value, the circuit of the motor is interrupted, and when the temperature attains a predetermined high value, the circuit is completed to the motor. The motor circuit includes a wire 5%, switch contacts 55, wire 56, motor 21, wire 57, solenoid 58 and a wire returning to the source of energy. It is apparent therefore that when the circuit to the motor is completed, the solenoid 58 will be energized. W'hen the solenoid 58 is energized, its magnet 59 will be attracted, opening a valve 60 in the pipe 28 through a link connection 61. When the motor circuitis interrupted, the circuit to the solenoid 58 will also be interrupted and the armature 59 will be pulled away from the solenoid 58 preferably by a spring 62, thus closing the valve 60 to prevent further flow of refrigerant from the receiver 25 to the evaporator 27.

When the refrigerant medium within the evaporator 27 is relatively warm, the passage provided by the orifice 40 is relatively large, therefore a relatively large quantity .of refrigerant is delivered to the evaporator 27, thus maintaining a relatively high back pressure within the evaporator 27 and the pipe 22. In this manner refrigerant having a high density will be conducted to the compressor 20 which in effect provides high efficiency in operation. Likewise, as the tem perature of the refrigerant in the evaporator decreases, vaporization decreases at this time, and it is desirable to decrease the quantity of refrigerant delivered to the evaporator in order to prevent flooding thereofand overflow of liquid refrigerant to the compressor. Disc 35 is subjected to the temperature of the refrigerant in the evaporator and as the temperature of said refrigerant decreases, the disc will contract to decrease the size of the orifice 40.

Therefore, the amount of refrigerant delivered to the evaporator decreases in accordance with the decrease in temperature of the refrigerant. In this manner excessive amounts of refrigerant will not be delivered to the evaporator to flood same. By virtue of the construction shown and described herein, such quantity of refrigerant is delivered to the evaporator 27 to maintain a high degree of efficiency in operation.

From the foregoing it is apparent that the present invention has certain advantages in that no movable parts are necessary for the valve. Thus the cost of the pressure reducing valve can be materially reduced. Also, by providing a variable opening for the valve, the proper amount of refrigerant is delivered to the evaporator for maintaining a high degree of efficiency in operation. And it is apparent that such a variable opening is provided simply by providing a disc having a high coefficient of expansion. This disc is preferably formed of a durable material such as copper alloyed with a hardening material such as antimony.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A refrigerating system, comprising in combination. an evaporator; means for withdrawing refrigerant medium from the evaporator and for compressing and condensing said refrigerant medium and for forcing the same into said evaporator; and means for regulating the flow of said medium to the evaporator including a memher having a high coefficient of expansion and having a centrally contractible passage for refrigerant medium said member being in a position to be affected by the temperature of the evaporator.

2. A refrigerating system comprising means for receiving refrigerant at low pressure and delivering it at high pressure, a condenser receiving refrigerant at high pressure from said means, an evaporator receiving refrigerant from said condenser and returning it to said means, and a disklike member having a relatively high coefficient of expansion and provided with a throttling aperture interposed between said condenser and evaporator where said member is affected by the temperature of said evaporator. I

3. A refrigerating system comprising means for receiving refrigerant at low pressure and delivering it at high pressure, a condenser receiving refrigerant at high pressure from said means, an evaporator receiving refrigerant from said condenser and returning it to said means, a disk-like memher having a relatively high coefiicient of expansion and provided with a throttling aperture interposed betwen said condenser and evaporator where said member is affected by the temperature of said evaporater, and means operable from the exterior of said system forcleaning said aperture.

4. A refrigerating system comprising means for receiving refrigerant at low pressure and delivering'it'at high pressure, a condenser receiving refrigerant at high and for sealing said aperture when diseonnecting said' system.

In testimony whereof I hereto aflix my signature.

FRANK W. ANDREWS. 

